The present invention relates generally to aquaculture, and more specifically to a fish tank system or apparatus, comprising a plurality of fish tanks and a measuring device for detecting at least one parameter of the water in the fish tanks. Another aspect of the present invention is a measuring device for such a fish tank system and related method for monitoring a plurality of fish tanks.
Overfishing of natural fish reserves and the associated stagnation, or even decline of fisheries yields, necessitates the relocation of fish production to other fields, and the refinement of such alternative fish production methods.
The possibilities of fish breeding and fish feeding in aquacultures basically provides a meaningful alternative to fishing natural fish stocks, and thus permits the preservation of natural fish stocks. In the course of history, several holding systems have been developed for producing aquatic organisms. These include classic fish ponds, launder systems, net pens and recirculation systems. Aquaculture production has increased steadily worldwide in recent years, while fisheries yields have stagnated as a result of the generally uncontrolled fishing and pollution of waterbodies.
In recirculation systems, and to a certain extent in other holding systems as well (ponds, launder systems or net pen aquaculture), ensuring abiotic parameters is a major challenge. This includes the constant maintenance of good water quality in the holding system. Constructing a fish tank with a three-part structure comprising a sedimentation section, a bioreactor section and a fish holding section between these two sections is generally known from DE 195 21 037 A1. Water flows in a constant stream through the three sections, in a sequence defined by the geometrical layout, which is from the bioreactor section into the fish holding section and on to the sedimentation section. Solids are sedimented out of the water in the sedimentation section, and can then be removed from circulation via a discharge line disposed in the bottom of the sedimentation section. In the bioreactor section, enrichment of the water with oxygen is achieved by injecting air, and intensive decomposition of organic matter by microorganisms is achieved.
Yet environmental factors, fish population growth in the fish tank and other, temporary events, such as feeding at periodic intervals, may lead to water parameters that are important for the health and development of the fish, such as oxygen, pH, nitrite concentration, fluctuating and leaving a predetermined optimal range.
Removing a water sample from a fish tank and analysing the water sample in order to adjust the above noted water parameters on the basis of such analysis is a known way of avoiding the aforementioned disadvantages. However, such testing has the disadvantage that the analysis of each individual fish tank at the required frequency would lead to aquaculture operations that are uneconomical, at least in large aquacultures comprising several fish tanks.